Police in Edinburgh are appealing for anyone with information to come forward following a serious assault in the city centre.
The incident took place around 2am on Sunday, December 3rd, at the junction of George IV Bridge and Chambers Street, near the National Museum of Scotland.
A 21-year-old man was attacked and attended the Edinburgh Royal Infirmary, where he was treated for a serious injury to his head.
Officers are eager to trace a group of four men, who were last seen walking northbound on George IV Bridge, as part of the ongoing investigation.
Detective Constable Iain Wallace of Gayfield CID said: "We're currently working to establish the full circumstances surrounding this assault and are eager to trace anyone who may have witnessed this.
"We believe that a passer-by may have video footage or images of the attack on his mobile phone and would urge this person to get in touch with us as soon as possible to help with our enquiries."
Those with information can contact Police Scotland on 101, quoting incident number 0607 of 3rd December, or report this anonymously to the charity Crimestoppers on 0800 555 111.